During the advancement or manipulation of a pipe string in a wellbore such as a drillstring or a coil tubing string, it is often prudent to jar, vibrate, or oscillate the pipe string. This vibration aids in overcoming frictional forces between the pipe string and the interior surface of the wellbore.
Various types of vibrator devices have been employed with pipe strings in order to provide vibration. Some such vibrator devices typically employ reciprocating impact elements that move back and forth along the axis of the pipe string to induce vibration in the pipe string. Other such vibrator devices employ the use of eccentrically weighted rotating masses, eccentric shafts or rods, or rotatable impact elements that rotate about the longitudinal axis of the drill or pipe string to strike an impact anvil in order to apply a rotational or torsional vibration to the pipe string. Vibrator devices of these types typically generate vibration to a localized segment of the pipe string.
Still other types of vibrator devices utilize Moineau power sections that are generally used in downhole mud motors or pumps. Moineau power sections typically utilize rubber or rubber-like elastomers as seals which are negatively affected by elevated wellbore temperatures and pressures, certain drilling fluids and or chemicals, and contaminants or debris in the wellbore or drilling fluids.
Consequently, there is a need for a pipe string vibrator that will serve to induce vibration to a much larger percentage of the pipe string or the entire pipe string without being susceptible to the negative effects of temperature and pressure and other factors associated with a wellbore environment.